diff --git a/include/nana/gui/widgets/treebox.hpp b/include/nana/gui/widgets/treebox.hpp
index 9901e1bf..2f4fe7d7 100644
--- a/include/nana/gui/widgets/treebox.hpp
+++ b/include/nana/gui/widgets/treebox.hpp
@@ -1,7 +1,7 @@
 /**
  *	A Tree Box Implementation
  *	Nana C++ Library(http://www.nanapro.org)
- *	Copyright(C) 2003-2016 Jinhao(cnjinhao@hotmail.com)
+ *	Copyright(C) 2003-2017 Jinhao(cnjinhao@hotmail.com)
  *
  *	Distributed under the Boost Software License, Version 1.0. 
  *	(See accompanying file LICENSE_1_0.txt or copy at 
@@ -110,17 +110,14 @@ namespace nana
 
 				struct pseudo_node_type{};
 
-				typedef widgets::detail::tree_cont<treebox_node_type> tree_cont_type;
-				typedef tree_cont_type::node_type	node_type;
+				using tree_cont_type = widgets::detail::tree_cont<treebox_node_type>;
+				using node_type = tree_cont_type::node_type;
 
 				trigger();
 				~trigger();
 
 				implement * impl() const;
 
-				void auto_draw(bool);
-				void checkable(bool);
-				bool checkable() const;
 				void check(node_type*, checkstate);
 				bool draw();
 
@@ -136,7 +133,6 @@ namespace nana
 				node_type* insert(node_type*, const std::string& key, std::string&&);
 				node_type* insert(const std::string& path, std::string&&);
 
-				bool verify(const void*) const;
 				bool verify_kinship(node_type* parent, node_type* child) const;
 
 				void remove(node_type*);
@@ -148,7 +144,6 @@ namespace nana
 				node_image_tag& icon(const ::std::string&) const;
 				void icon_erase(const ::std::string&);
 				void node_icon(node_type*, const ::std::string& id);
-
 				unsigned node_width(const node_type*) const;
 
 				bool rename(node_type*, const char* key, const char* name);
diff --git a/source/gui/widgets/treebox.cpp b/source/gui/widgets/treebox.cpp
index 76f6dc20..c7aeba61 100644
--- a/source/gui/widgets/treebox.cpp
+++ b/source/gui/widgets/treebox.cpp
@@ -1,7 +1,7 @@
 /*
  *	A Treebox Implementation
  *	Nana C++ Library(http://www.nanapro.org)
- *	Copyright(C) 2003-2015 Jinhao(cnjinhao@hotmail.com)
+ *	Copyright(C) 2003-2017 Jinhao(cnjinhao@hotmail.com)
  *
  *	Distributed under the Boost Software License, Version 1.0.
  *	(See accompanying file LICENSE_1_0.txt or copy at
@@ -1562,35 +1562,6 @@ namespace nana
 					return impl_;
 				}
 
-				void trigger::auto_draw(bool ad)
-				{
-					if(impl_->attr.auto_draw != ad)
-					{
-						impl_->attr.auto_draw = ad;
-						if(ad)
-							API::update_window(impl_->data.widget_ptr->handle());
-					}
-				}
-
-				void trigger::checkable(bool enable)
-				{
-					auto & comp_placer = impl_->data.comp_placer;
-					if(comp_placer->enabled(component::crook) != enable)
-					{
-						comp_placer->enable(component::crook, enable);
-						if(impl_->attr.auto_draw)
-						{
-							impl_->draw(false);
-							API::update_window(impl_->data.widget_ptr->handle());
-						}
-					}
-				}
-
-				bool trigger::checkable() const
-				{
-					return impl_->data.comp_placer->enabled(component::crook);
-				}
-
 				void trigger::check(node_type* node, checkstate cs)
 				{
 					if (!node->owner) return;
@@ -1727,11 +1698,6 @@ namespace nana
 					return x;
 				}
 
-				bool trigger::verify(const void* node) const
-				{
-					return impl_->attr.tree_cont.verify(reinterpret_cast<const node_type*>(node));
-				}
-
 				bool trigger::verify_kinship(node_type* parent, node_type* child) const
 				{
 					if(false == (parent && child)) return false;
@@ -1744,7 +1710,7 @@ namespace nana
 
 				void trigger::remove(node_type* node)
 				{
-					if(!verify(node))
+					if (!tree().verify(node))
 						return;
 
 					auto & shape = impl_->shape;
@@ -1769,10 +1735,10 @@ namespace nana
 
 				void trigger::selected(node_type* node)
 				{
-					if(impl_->attr.tree_cont.verify(node) && impl_->set_selected(node))
+					if(tree().verify(node) && impl_->set_selected(node))
 					{
-						impl_->draw(true);
-						API::update_window(impl_->data.widget_ptr->handle());
+						if(impl_->draw(true))
+							API::update_window(impl_->data.widget_ptr->handle());
 					}
 				}
 
@@ -2160,6 +2126,8 @@ namespace nana
 	}//end namespace drawerbase
 
 	//class treebox
+		using component = drawerbase::treebox::component;
+
 		treebox::treebox(){}
 
 		treebox::treebox(window wd, bool visible)
@@ -2184,18 +2152,30 @@ namespace nana
 
 		void treebox::auto_draw(bool ad)
 		{
-			get_drawer_trigger().auto_draw(ad);
+			auto impl = get_drawer_trigger().impl();
+			if (impl->attr.auto_draw != ad)
+			{
+				impl->attr.auto_draw = ad;
+				if (ad)
+					API::refresh_window(this->handle());
+			}
 		}
 
 		treebox & treebox::checkable(bool enable)
 		{
-			get_drawer_trigger().checkable(enable);
+			auto impl = get_drawer_trigger().impl();
+			auto & comp_placer = impl->data.comp_placer;
+			if (comp_placer->enabled(component::crook) != enable)
+			{
+				comp_placer->enable(component::crook, enable);
+				get_drawer_trigger().draw();
+			}
 			return *this;
 		}
 
 		bool treebox::checkable() const
 		{
-			return get_drawer_trigger().checkable();
+			return get_drawer_trigger().impl()->data.comp_placer->enabled(component::crook);
 		}
 
 		void treebox::clear()